1. Field of the Invention
This invention relates to a magnetic valve, and more particularly refers to a new and improved three-way valve as a switching device for a multi-temperature cooling apparatus operated with only one refrigeration machine, with a tubular valve housing which has at least one inlet as well as several outlets and on which the coil of an electromagnet is mounted, when energized, acts on the armature which is axially movable in the housing.
2. Description of the Prior Art
In one known magnetic valve of the type mentioned, plugs made of elastic plastic material and disposed in metallic bushings are used as sealing organs. These bushings in turn are movably arranged in sleeves which are in turn supported, axially movably, in a tubular armature. The plugs and the sleeves are guided in the armature by radial securing pins, the ends of which engage in elongated holes in the wall of the armature. In this manner, the plugs and the sleeves have freedom of movement in the axial direction limited to the lengthwise dimension of the elongated holes. Between the sleeves and the bushings for the plugs, a system of three different coil springs are arranged, which are braced alternately against the bushings and the sleeves or, via these and the securing pins, against the armature. These three coil springs are supposed to match the restoring force of the armature to the magnet characteristic of the magnetic valve.
Because of its many parts, the design of the known magnetic valve is complicated and therefore expensive. In addition, its dimensions are relatively large and because of the system used therein with many moving parts and different compression springs, it is also particularly trouble-prone. The known magnetic valve furthermore requires considerable effort to assemble. The known magnetic valve is therefore expensive and has inherent risks, which makes it only conditionally useful as a switching device for the refrigeration machine in multi-temperature cooling apparatus if only because of the long guarantee periods customary in the industry.